Irritable Bowel Syndrome (IBS) is a life altering disorder of the intestines that effects approximately 20 percent of the general population. There is no single diagnostic test for positive confirmation of IBS. Physicians arrive at an lBS diagnosis following a protocol that uses standard endoscopic tests to exclude structural or biochemical abnormalities, a physical examination and a symptom questionnaire. This inefficient process leads to an enormous use of healthcare resources estimated at 3.5 million office visits and 2.2 million prescriptions at a direct and indirect cost of $29 billion annually. Our objective is to develop an easy to use, low cost breath test to diagnosis lBS. The test developed by Metabolic Solutions (MSI) is based on the principle that lBS patients malabsorb fructose. In preliminary studies MSI has demonstrated a novel technology using a carbon 13 tracer and unlabeled fructose to identify individuals with lBS by whether or not they can absorb the administered fructose. This is the first test to assay fructose malabsorption directly from the small intestine and correlate it to the diagnosis of LBS. The proposed test will significantly reduce national health care expenditures because proper diagnosis will lead to fewer office visits, more prudent use of drugs and better general health and well-being for a large number of Americans.